Fuel pump



FUEL PUMP Filed Aug. 5, 1939 2 sheetssheet 2 ATTORNEY Patented UNITED STATES PATENT. OFFICE FUEL rum 7 Louis Beeh, Snrinrfleld, Mass. Application August 5, 1939, Serial No. 288,501

. 1 clai s.- (01. roe-m) This invention relates to fuel pumps for internal combustion engines of the type in which fuel is injected into the engine cylinder or into the air inlet during each suction stroke of the engine pistons. Engines of this type are well known but are not in commercial competition with automotive engines of the carburetter type due to the greater cost of the fuel pump as heretofore constructed in comparison with the cost it) of a carburetter and also due to the difficulty of accurately measuring the small quantities of fuel required by such engines-per working stroke.

It is a primary object of the present invention to provide a fuel pump for engines of this type is which is of simple construction and which can be easily and cheaply manufactured and assembled.

It is among the objects of this invention to provide a fuel pump which is so compactly arranged 2 that it is suitable for automotive purposes and may be mounted in the relatively small space.

available for the-auxiliary equipment of such engines.

It is a further object of the invention to pro- 25 vide a pump of the type described which is readily accessible for servicing of all parts and in which all parts subject to wear may be readily removed for replacement or repair. I

A further object of theinvention resides in the 3" provision of a simple structure for simultaneously varying the quantity of fuel supplied to each of the cylinders of a multi-cylinder engine.

The invention further resides in novel structural features the nature and advantages of i which will in part be apparent and in part more particularly pointed out in the following detailed description.

Referring to the accompanying drawings, Figure '1 illustrates partly in section and partly in 4 side elevation, a fuel pump and one of the cooperating fuel nozzles constructed in accordance with the invention.

Figure 2 is a bottom plan view with parts broken away to show internal construction.

Figure 3 is a vertical section through the pump Figure 4 is a detail showing the structure of the discharge valve of the pump.

In the drawings the fuel pump, which is indi- 5o cated generally at l, is mounted upon a shaft 2,

immediately below an ignition distributor 3. A pump body 4, formed of a single annular casting, is provided with a plurality of radial bores 5, forming the cylinders of the pump. A plurality s plungers 6, are reciprocatively mounted in the bores 5, each plunger being formed of a sleeve like portion 1, at one end, and a solid portion 8 forming the opposite end. The solid end portions 8 of the plungers are provided with longitudinally extending grooves 9 on the exterior surface thereof forming sliding gears, the function of which will later appear. The end portions .8 of the plungers 6 project inwardly of the pump body to contact an outer ring ill of a roller hearing assembly mounted upon an eccentric ii of 10 the shaft 2.

' a point immediately below the eccentric II. An

annular boss l6, Surrounding the bearing l4, centers the ball bearing l4 in its inner circumference, and also centers, on its outer circumference, a crown gear II the teeth of which are adapted to mesh with the teeth formed on the end portions 8 of the plungers G by the grooves 9. A plurality of pins II are attached to the crown gear i1 and extend through curved slots i9 in :5 the end plate l2 to connect with an actuating ring 20 mounted upon the exterior of the end plate l2. An enlarged portion 2i of the sleeve i3 serves to center the actuating ring 20, and a lever 22, integral with or rigidly attached to the 80 ring 20 is provided for angularly adjusting the actuatingring 20 and correspondingly rotating the crown gear i1.

An upper end plate 23 is provided with an internal shoulder 24 which centers a ball bearing 85 25 for the shaft 2 at a point immediately above the eccentric 'll. Machine screws 26, extend through the end plates i2 and 23 and are screwed into threaded bores in the body portion 4 to secure the end plates to the body portion and gas- 40 kets 49 insure a fluid tight seal at the joints so formed. Concentric annular bosses 21 and 28 on each side of the body 4 space the end plates from the body to provide two annular chambers therebetween. The lower of these chambers indicated at 29, provides a suction chamber and is in communication with -a supply tank (not shown) by way of a supply pipe 30. The other chamber,-indicated at ll, provides a by-pass chamber which is in communication with the 50 supply tank by way of a return pipe 32,

A plurality of externally threaded annular bosses 33 formed integral with the body portion 4, and forming extensions of each of the bores '5, project radially from the body 4 for some disl tance beyond the outer circumference of the body and of the end plates I2 and 23. Reduction nipples 34 on the bosses 33 form connections be tween the pump cylinders and the discharge pas- 5 sages 35 which lead to suitable fuel nozzles 33 which discharge either into the engine cylinders or adjacent the inlet valves thereof. The reduction nipples 34 also serve to holdgclosing disks 31 on the end of the bosses 33 to eflfectively close the open end of the pump cylinders formed by bores Ii except for the discharge openings 33pmvided in eachdisk 31. A discharge valve 33 formed in a manner hereinafter more particularly described. is adapted to closethe opening I 33. Passages 40 extend from the annular suction chamber 23 to each of the pump cylinders! 1 of each plunger are adapted to register with.

the passage 40 when the pump plungers 3 are in their innermost position. A plurality of passages 42 are likewise provided between each pump cylinder and the by-pass chamber 31, while oblique slots 43 formingpassages through the sleeve like portion of the plungers are adapted as to register with the passages 42 during the later portion of the discharge-stroke ,of the plungers. Springs 44, within the sleeve like portions 1 of the plungers and bearing against the closing disks =31, maintain the'inner ends of the plungersin contact with the bearing ring III of the eccentric Referring to Figure 4, it will be seen that each of the discharge valves 39 is formed from a thin disk of spring metal, aportion of which is cut 5 out, as indicated at 45, leaving an outer peripheral rim 46 and a central tongue 41 which tongue is adapted to cover the discharge opening 38 in the disk 31. In order to prevent relative rotation of the disk 31 and the valve 39, the valve 0 has a notch 48 adapted to register with a raised portion on the disk and thus maintain the two members in such registry that the tongue 41, will always cover the opening 38.

The fuel nozzle indicated generally at 36 in a Figure 1 is of simple construction and, when the pump is used to supply fuel to the air inlet of an engine, it may be of the type commonly known as an open nozzle. Where the fuel is to be injected directly into the engine cylinder, I guprefer to use the form shown having a check valve 50, similar in construction to the discharge valve 39 of the fuel pump. This check valve 50 is desirable to prevent the compression and explosion pressures in the engine cylinder from reacting upon the fuel line and pump connections.

In operation, the plungers 6 are driven outwardly through a fixed stroke by the eccentric Ill and returned inwardly by the springs 44 in so the usual manner. During the inward or return stroke of a plunger a partial vacuum is created in the corresponding pump cylinder'and upon reaching its innermost position, the passage 4l moves into register with the passage 40 and fuel 66 from the suction chamber 29 is drawn into the pump cylinder. Upon the outward movement of the plunger fuel is forced through opening 38 in the disk 31 against the action of the valve 39 and thence through the discharge passage 35 and 70 the nozzle 36 which opens either into the working cylinder of the engine or at a point adjacent the intake valve thereof. This action continues until the oblique slot 43 registers with the opening 42 at which point the supply of fuel to the 7 engine terminates abruptly and during the remainder of the outward stroke of the piston' fuel from the pump cylinder passes into the annular -by-pass chamber 3| from which it is returned to the supply tank by way of the passage 32.

Angular adjustment of the lever 22 and the attached actuating ring 23 produces a correi that in the event of failure of any one of the pump members, the defect may be remedied by removing the reduction nipple 38 which will permit the insertion of a new discharge valve, or a new plunger as necessary without removing the pump from the engine to which it is attached.

It will also be seen that the structural features described result in a simple pump structure which occupies but a small space and which may readily be applied to existing engine structures without material alteration thereof.

Simplicity of construction and ease of manufacture will be particularly apparent in the structure of the pump body 4 which comprises a single casting forming an annular web having no internal cavities which would be likely to involve difficulty or expense in the casting thereof. The provision of the suction and by-pass sumps between the body portion and the end plates is a material factor in the simplicity of the design inasmuch as this helps to avoid internal cavities in the casting and also permits access to passages 4| and 42 should one of them become clogged.

Although there is herein described but a single preferred embodiment of the invention, other embodiments within the scope of the appended claims will be obvious to those skilled in the art from a consideration of the form shown. The invention has been described in conjunction with a fuel pump of the.type commonly known as a radial cylinder pump. It will be obvious to those skilled in the art that certain of the features of the invention are not limited to pumps of this type but are applicable to pumps generally, and other aspects are applicable to pumps of the general type in which the capacity thereof is altered by a relative rotation between the pump piston and the pump cylinder.

Having thus described the invention, I claim: 1. A fuel pump comprising an annular web having a plurality of bores extending radially therethrough, plungers reciprocative in said bores, 0 a shaft extending through the central opening of said annular web and having an eccentric adapted to actuate said plungers, end plates removably fastened to each side of said annular web and having internally shouldered portions, and ball bearings centered in each of said shouldered portions providing journals for said 'shaft upon each side of said eccentric.

2. A fuel pump of the type having a plurality of pistons extending. radially from a central shaft, a pump body having radial bores forming pump cylinders, integral annular bosses projecting outwardly from the outer circumference of said body and forming a prolongation of each bore, a reduction nipple on each boss having internal threads coacting with external threads upon said boss, and a pair of disks secured on the end of each boss by the corresponding nipple, one of said disks forming a closure for said pump cylinder and the other forming a discharge valve covering an opening in said closure. v

3. A fuel pump comprising an annular web having a plurality of bores extending there'- through, plungers reciprocative in said bores, lateral passages extending from. each of said bores .to each side of said annular web, end plates attached to each side of said web and forming therewith annular channels on each side thereof, each of said lateral passages extending to one of said chambers.

4. A fuel pump comprising an annular web having a plurality of bores extending therethrough, plungers reciprocative in said bores, said web also having lateral passages extending from each of said bores to each sidethereof, plates attached to each side of said web and forming therewith a pair of annular channels, said lateral passages opening into said channels, annular bosses projecting from the circumference of said'web and forming extensions of said bores, a discharge connection threaded upon each boss, a discharge valve clamped betweenveach connection and the end of each boss.

5. A fuel pump comprising an annular web having a plurality of cylinder bores extending radially therethrough, plungers reciprocative. in said bores, a plate-fastened to one side of said web forming therewith an annular suction chamber and a plate fastened to the opposite side of saidweb forming therewith an annular by-pass chamber.

6. A fuel pump comprising an annular web having a plurality of cylinder bores extending radially therethrough, plungers reciprocative in said bores, plates fastened to each side of said web and forming therewith annular suction and by-pass chambers, a crown gear supported on the innerface of one of said plates, said pistons having end portions coacting with said gear. and means extending through said last mentioned plate for rotating said gear.

7. A fuel pump comprising an annular web having a plurality of cylinder bores extending radially therethrough, plungers reciprocative in said bores, a plate detachably secured to one side of said web forming therewith a suction chamber and a plate detachably secured to the opposite side of. said web forming therewith a by-pass chamber. 1

LOUIS BEEH. 

